Author Topic: I'm Confused by Load Data for 7625  (Read 374 times)

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Offline Smitty79

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I'm Confused by Load Data for 7625
« on: September 24, 2019, 04:06:01 PM »
I've loaded about 15 lb 7625 with 147gn bullets.   I am switching to 125gn SNS conical flat point.   I can load these to 1.13 OAL.   I went to the Hodgdon site for load data and found 4 bullets in 124 or 125 grain.   The max load data is all over the place.

   
124 GR. BERB HBRN TP  Max Charge 4.9   OAL 1.15  Velocity 1054

125 GR. HDY HAP  Max Charge 3.8    OAL  1.069   Velocity  914

125 GR. LCN   Max Charge 4.1   OAL 1.125 Velocity 1035

125 GR. SIE FMJ  Maz Charge  4.1   OAL 1.125   Velocity 1035

I was figuring that I'd have no problem getting 132 pf with 7625 since it is considered slower than Titegroup and others I've used.   I guess not.   I am really wondering about the one bullet with the 4.9 charge.    Years ago, I went up around 4.5gns with some 124/5 bullets.   I don't know if the on line data has changed or if I was pushing it harder than I should have.

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Offline Wobbly

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Re: I'm Confused by Load Data for 7625
« Reply #1 on: September 24, 2019, 04:16:51 PM »
I love 7625, and we don't hear enough about it anymore.

The short answer is that all that data was transferred to Hodgdon from IMR, and IMR seems to have done a lot of that testing in the early 1990's. So I wouldn't trust any of it.

>  There are several threads on this forum using 124gr and 147gr if you'll do a simple search on "7625" or "IMR 7625". Velocities on 124gr up to 1050fps, which is more than enough.

>  Or, get a chrono and build your own test based on their listed Max Velocity.

Hope this helps.  ;)
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Offline Smitty79

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Re: I'm Confused by Load Data for 7625
« Reply #2 on: September 24, 2019, 04:55:49 PM »
I’ve found 4.8 on Enos without anyone complaining that it’s too much.   Given the comments about lot variability, I expect to be at reasonable pressures up to a velocity of 1050 with these bullets and OAL. .   What do you think?
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Offline Pistolet

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Re: I'm Confused by Load Data for 7625
« Reply #3 on: September 24, 2019, 05:12:22 PM »
I've loaded about 15 lb 7625 with 147gn bullets.   I am switching to 125gn SNS conical flat point.   I can load these to 1.13 OAL.   I went to the Hodgdon site for load data and found 4 bullets in 124 or 125 grain.   The max load data is all over the place.

   
124 GR. BERB HBRN TP  Max Charge 4.9   OAL 1.15  Velocity 1054

125 GR. HDY HAP  Max Charge 3.8    OAL  1.069   Velocity  914

125 GR. LCN   Max Charge 4.1   OAL 1.125 Velocity 1035

125 GR. SIE FMJ  Maz Charge  4.1   OAL 1.125   Velocity 1035

I was figuring that I'd have no problem getting 132 pf with 7625 since it is considered slower than Titegroup and others I've used.   I guess not.   I am really wondering about the one bullet with the 4.9 charge.    Years ago, I went up around 4.5gns with some 124/5 bullets.   I don't know if the on line data has changed or if I was pushing it harder than I should have.

Help me wizards!
I'm still learning and I am wondering why BERB HBRN TP which is a plated bullet has a bigger max charge than the jacketed ones.Is there a logic to this? ??? ???

Offline Smitty79

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Re: I'm Confused by Load Data for 7625
« Reply #4 on: September 24, 2019, 05:31:02 PM »
Pistolet,

The Enos forums say that 7625 has high lot variation.   If those came through different lots, that could account for this.
« Last Edit: September 24, 2019, 07:53:20 PM by Smitty79 »
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Offline Wobbly

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Re: I'm Confused by Load Data for 7625
« Reply #5 on: September 25, 2019, 08:56:24 AM »
I’ve found 4.8 on Enos without anyone complaining that it’s too much.   Given the comments about lot variability, I expect to be at reasonable pressures up to a velocity of 1050 with these bullets and OAL.   What do you think?

Actually, 7625 is a very low pressure powder due to the absence of the highly reactive nitroglycerin. This is easy to see in the 7625 shotgun loads, which show a HUGELY lower chamber pressure for the same shot speeds.

I'd want to question the assertion of lot-to-lot variability in the age of computer controlled processing. That simply doesn't make sense, and may well be an internet rumor held over from the 1950's or something started by a competitor. Three people see the same comment on one board, then rush over to another forum to repeat it. All of a sudden the second forum has a quorum which all seem to agree on a single subject. (BTW... Donald Trump really IS a Russian spy because I heard it on NPR and read it in the NY Times.) The internet is a wasteland of rumor repetition by people who simply cannot think for themselves. Consider that IMR got the formula for 7625 from DuPont, one of the largest chemical companies in the world, and prime contractor to the US military. Remember the "worms in McDonald's hamburger meat" rumor ? Number one is always being shot at by jealous competitors.

I'm using 4.7gr under my PD 124gr which is loaded at 1.100".

 ;)
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Offline Wobbly

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Re: I'm Confused by Load Data for 7625
« Reply #6 on: September 25, 2019, 09:33:19 AM »
I'm still learning and I am wondering why BERB HBRN TP, which is a plated bullet, has a bigger max charge than the jacketed ones. Is there a logic to this?


The Berry HBRN is the newest bullet shown, and therefore is the result of the most modern testing. The HBRN has been introduced since I've been a moderator here. In fact, Berry was a sponsor of this board. We received some of the very first HBRN bullet samples and tested them for this very same forum.

Generally speaking, plated bullets are softer than jacketed. While they generally fall in hardness between Lead and Jacketed, they are much more akin to lead because a jacket is rolled and "work hardened", whereas the plating is pure alloy deposited onto a lead core one molecule at a time via the plating process. So although the plating may be thick and "tough", it will never be truly "hard".

I say all that to get you to understand that a soft bullet conforms to a barrel faster and therefore starts to move down the barrel sooner than a hard bullet. Moving sooner means that for the same load, pressures are lower. Therefore loads must go higher to move them at equivalent speeds.

Secondly, if you are looking at the posted data, notice that no ownership is assigned to the LCN bullet. That could be anybody's bullet, cast or struck, and with any type of lube.
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Offline Smitty79

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Re: I'm Confused by Load Data for 7625
« Reply #7 on: September 25, 2019, 10:44:02 AM »
I’ve found 4.8 on Enos without anyone complaining that it’s too much.   Given the comments about lot variability, I expect to be at reasonable pressures up to a velocity of 1050 with these bullets and OAL.   What do you think?

Actually, 7625 is a very low pressure powder due to the absence of the highly reactive nitroglycerin. This is easy to see in the 7625 shotgun loads, which show a HUGELY lower chamber pressure for the same shot speeds.

I'd want to question the assertion of lot-to-lot variability in the age of computer controlled processing. That simply doesn't make sense, and may well be an internet rumor held over from the 1950's or something started by a competitor. Three people see the same comment on one board, then rush over to another forum to repeat it. All of a sudden the second forum has a quorum which all seem to agree on a single subject. (BTW... Donald Trump really IS a Russian spy because I heard it on NPR and read it in the NY Times.) The internet is a wasteland of rumor repetition by people who simply cannot think for themselves. Consider that IMR got the formula for 7625 from DuPont, one of the largest chemical companies in the world, and prime contractor to the US military. Remember the "worms in McDonald's hamburger meat" rumor ? Number one is always being shot at by jealous competitors.

I'm using 4.7gr under my PD 124gr which is loaded at 1.100".

 ;)

Thanks Wobbly.   Your response that the Berry's bullet is newest makes me think that it is also likely the most accurate.   Given that I'm using softer, coated, bullets, I should be fine to 4.8 grains at the 1.13 OAL I am loading to.
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Offline Wobbly

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Re: I'm Confused by Load Data for 7625
« Reply #8 on: September 25, 2019, 09:32:15 PM »
Thanks Wobbly.   Your response that the Berry's bullet is newest makes me think that it is also likely the most accurate.   Given that I'm using softer, coated, bullets, I should be fine to 4.8 grains at the 1.13 OAL I am loading to.

I think I'd want to chrono that one just to be sure. Just wondering why you are starting at near the max ?
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Offline Smitty79

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Re: I'm Confused by Load Data for 7625
« Reply #9 on: September 26, 2019, 09:02:15 AM »
I started at 4.0 gns.   I'm stopped at 4.4.   Average velocity is 1027.   I'd like to get to 1050.
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Offline Smitty79

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Re: I'm Confused by Load Data for 7625
« Reply #10 on: September 26, 2019, 08:53:51 PM »
4.6 have me 1050.  I'm happy.
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Offline Wobbly

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Re: I'm Confused by Load Data for 7625
« Reply #11 on: September 26, 2019, 09:31:56 PM »
Very good !!
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